This invention relates in general to rotor tillers or cultivators. More particularly, this invention relates to a skirt assembly comprising a pair of shields disposed along the sides of a rotor tiller which prevent plants from being covered with dirt or entangled with the tines of the rotor tiller during operation of the tiller. Specifically, the invention relates to a skirt assembly having a pair of shields connected by a framework which may be installed on the guard panel or deck of a rotor tiller either in the course of manufacturing or by retrofitting it onto an existing tiller, the shields of which are individually adjustable and free-floating.